Fix non-blocking Socket#connect on Unix - #17436
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The macOS 26.7 release has a bug where non-blocking socket connections may complete with EISCONN (connected) when it actually failed (sic). Adds a second check for the actual error state (SO_ERROR) of the socket after EISCONN, which apparently catches the issue. Co-Authored-By: nogginly <19142777+nogginly@users.noreply.github.com>
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I suppose there is no reason to check with |
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Now io_uring also raises on EISCONN 👍 There's indeed no need to check for |
straight-shoota
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Sep 21, 2026
Socket#connect on Unix
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The macOS 26.7 release apparently has a bug where non-blocking socket connection may complete withSee https://forum.crystal-lang.org/t/socket-connection-error-after-macos-26-7-update/9145EISCONN(connected) when it actually failed (sic).EDIT: Our non-blocking loop for
Socket#connectis wrong: unlike other operations,connectmusn't be re-tried after waiting, it's actually asynchronous, and we must check the socket error state after waiting for the socket to become writable. See connect(2).Adds a second check for the actual error state (SO_ERROR) of the socket after EISCONN.
This apparently catches the issue.Adapted from https://github.com/nogginly/socket_connect_fix.cr/blob/b22e7df11d3911be9f04f4a9fc5ff8de0c829e2d/src/socket_connect_fix.cr by @nogginly